<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
        <script src="./vue.js"></script>
        <style>
            .active{
                color: red;
            }
        </style>
    </head>
    <body>
        <div id="app">
            <ul>
                <!-- btnClass(index,item)  传入的参数是什么得到的就是什么参数值 -->
				<!-- 如果还想得到事件对象 event   传入$event -->
                <!-- :class="{active:currentIndex === index}"  判断是否绑定一个active -->
                <li v-for="(item,index) in movies" :class="{active:currentIndex === index}" @click="btnClass(item,index,$event)" :key="index">
                    {{item}}
                </li>
            </ul>
        </div>
    </body>
    <script>
        let app = new Vue({
            el:"#app",
            data:{
                msg:"nihao",
                movies:[
                    '西游记',
                    '三国演义',
                    '红楼梦',
                    '水浒传'
                ],
                currentIndex:0 //搞一个变量  记录状态 默认谁是红色
            },
            methods: {
                btnClass:function(item,index,event){
                    console.log(item);
                    console.log(index);
                    console.log(event);
                    this.currentIndex = index;
                }
            }
        })
    </script>
</html>